http://www.livecapoeira.com/capoeira-videos/1/Capoeira-roda-turns-into-a...

Basically I saw this video and was wondering if this is typical in capoeira to have fights end up happening? I realize that the entire event wouldn't normally go all haywire, but is it common for the capoeira roda to get a bit heated?

Anyone have any tips on avoiding this or stories about something similar?